In general, a fuel cell is formed with a power generating device that has an electrolyte film and electrode films (a fuel electrode and an air electrode) placed on both side of the electrolyte film, and separators that have fluid passages for supplying fuel gas (hydrogen) and oxide gas (oxygen, normally the atmosphere) to the electrode films. A solid polymer electrolyte fuel cell has a fuel cell stack that is formed by stacking fuel cells of the above-described type.
FIG. 11 is a cross-sectional view of a conventional fuel cell 100 that has a power generating device 300 interposed between a separator 200A and a separator 200B. Since the volt age is too low in the single cell 100, several cells of this type are stacked to form a fuel cell stack.
The power generating device 300 includes a fuel electrode 300A that is located to face the separator 200A for fuel gas supply, an air electrode 300B that is located to face the separator 200B for oxide gas supply, and an electrolyte film 300C that is interposed between the fuel electrode 300A and the air electrode 300B.
FIG. 12 is a plan view of a conventional separator 200.
The separator 200 has a gas channel 201 having a number of concave grooves formed in the center of the surface of a separator main body 205. Also, manifolds 202 that penetrate the separator main body 205 in the stacking direction are provided on both sides of the gas channel on the surface of the separator main body 205. Gas is supplied to the gas channel 201 via the manifolds 202.
Connecting paths 203 that connect the concave grooves of the gas channel 201 to the manifolds 202 are formed between the gas channel 201 and the manifolds 202.
Each of the connecting paths 203 is formed in a tunnel-like fashion with grooves 203a that connects the gas channel 201 to the manifolds 202, and a plate member 203b that covers the openings of the grooves 203a. 
A gasket 204a that is made of an elastic material, surrounds the gas channel 201, and prevents gas leakage from the gas channel 201 to the outside, is formed on the surface of the separator main body 205.
Also, a gasket 204b that is made of an elastic material is formed at the peripheral portion of the manifolds 202, including the surface of the plate member 203b that covers the grooves 203a. Accordingly, the gas to be supplied from the manifolds 202 to the connecting paths 203 is prevented from leaking to another separator 200 stacked on the separator 200 or to the power generating device 300 interposed between the separators.
As the plate member 203b covers the grooves 203a and the gasket 204b is provided on the surface of the plate member 203b, the plate member 203b is pushed onto the grooves 203a by virtue of the repulsive force of the gasket 204b against the compression force applied from the other separator 200 stacked on the upper surface of the gasket. Thus, the connecting paths can be hermetically sealed.
If an adhesive agent is used to secure the plate member 203b to a predetermined position on the upper surface of the grooves 203a of the separator 200, the adhesive agent might stick out to the grooves 203a, and defective bonding is caused, resulting in a deterioration in quality. Therefore, the plate member 203b is engaged with the upper surface of the grooves 203a without an adhesive agent, and the gaskets 204a and 204b made of an elastic material are integrally molded in a series at the entire peripheral portion of the manifolds 202, including the surface of the plate member 203b. In this manner, the plate member 203b is secured to a predetermined position on the upper surface of the grooves of the separator 200. A fuel cell separator with this structure has been known (refer to Patent Document 1).
[Patent Document 1] Japanese Unexamined Patent Publication No. 2002-50364